Vitamin D and Disease Perception Outcomes in a Cluster of Patients with High-Disease-Activity Chronic Spontaneous...

Background/Objectives: Chronic Spontaneous Urticaria (CSU) is a skin disorder marked by recurrent wheals and itching, with or without angioedema, which can greatly affect the quality of life. Vitamin D has been implicated in the pathophysiology of various immune-mediated conditions, including CSU. The connection between vitamin D levels, patients' perceived symptoms, and life impact remains unexplored. This study aims to elucidate vitamin D levels and their correlation with perceived disease-related burden in individuals with CSU. Methods: PROM-based questionnaires, serum 25(OH)D levels, and BMI were statistically analyzed in high-disease-activity CSU, among hospitalized and outpatients who attended the main tertiary hospital center during a 1-year period. These data were compared with a control group, after obtaining their consent. Results: The study included 104 patients, 74 (71.15%) females, mean age 43.17 ± 18.26 years, and 23 controls, 12 (52.17%) females, mean age 44.61 ± 12.77 years. Levels of 25(OH)D were significantly lower in patients compared to controls and in the hospitalized versus the outpatient group (p < 0.05). Suboptimal 25(OH)D was found in 94.23% of patients (mean level 18.29 ± 6.74 ng/mL) and 82.61% of controls (mean 24.01 ± 7.44 ng/mL). A BMI > 25 kg/m² was found in 71 (68.3%) patients and 11 (47.83%) controls. Age was not significantly correlated with vitamin D levels. A significant positive correlation was found between vitamin D levels and the perceived bothersomeness score of urticarial elements and pruritus. Age was negatively correlated with perceived bothersomeness of pruritus. Irrespective of 25(OH)D levels, perceived bothersomeness of urticarial elements positively correlated with scores for angioedema, pruritus, and the impact of CSU on life and daily activities. Life and daily activities impact scores were also positively correlated with angioedema and pruritus. Conclusions: Suboptimal levels of 25(OH)D were common in CSU patients, especially among hospitalized patients, and were significantly lower compared with controls, suggesting a potential link between low vitamin D status and high disease activity. PROMs did not show a significant association between lower vitamin D levels and worse scores for perceived bothersomeness of urticarial elements, angioedema, pruritus, or impact on life and daily activities.